What are some rumours about them? What would the average person know or assume about them? What would the average person not know? (shouldn't know)
He and Indigo are in a relationship (they're Not)
Alternatively (sometimes Additionally), he and Indigo are siblings
He's a vampire (someone saw his fangsies when he yawned once and it happened to be a spooky looking night). This one is particularly amusing to Indi.
He visits his parents every month (just so happens to coincide with every full moon, not suspicious At All)
Olexa is his long lost daughter
He was somehow involved in the 'death' of Lisanna Strauss (given that he was an s-class member of the guild, close to her, and left the same year of that event, some people were Suspicious instead of empathetic)
He left Fairy Tail and joined Quatro Cerberus because he just really likes dogs
He has scars all over his body, which is why he is never really seen showing much skin (there is truth to this and it likely started because one of his scars is visible on his neck and collarbone depending on what he's wearing)
Common knowledge (things most people would/could know):
He was a member of Fairy Tail and is a current member of Quatro Cerberus
He runs a shop called the Chimera Collection and crafts everything himself
His closest friend and teammate is Indigo
He holds classes/workshops sometimes and often visits markets/fairs (people might see him there)
He is quiet and generally pretty chill
Based on his reputation and common knowledge, one can assume he is reliable, skilled, reserved, and is maybe hiding something.
If one believes the rumours, they might assume he has some sort of Relationship with Indigo, or that he is hiding some dark past
One might also assume he doesn't ever show a temper or get angry, because he's always mentioned as being rather calm or relaxed. They might think he's a bit of a pushover, that he might not stand up for himself.
As he's a former member of FT, they might assume he'll give discounts to FT members, as well as those from his current guild.
Since he is regularly commissioned by famous or wealthy people, it might be assumed that he might know some of their secrets or have some other connection with them.
Not common knowledge (things most people don’t/wouldn’t know):
The wolf fusion. Unless they were a member of FT at the time it happened (or are a current member that has been told the story), or are a member of QC (or are connected to it) or are Master Bob or Porlyusica, they won't know what happened. (this can change with plotting, i accept that certain muses might be able to sense something about it)
Where he actually goes when the full moon is approaching and that the moon is the reason for his disappearance.